I'm using this for the second half of letting authors generate fake faces for their fictional characters and then putting those faces on top of video snippets from actors. I'm still in the exploratory stages of what all is possible/useful, but feedback so far has been generally positive ("characters feel more real", "easier to empathize", "super interesting potential").

Could also make for some interesting low-budget book commercials/trailers where authors (or I guess anyone making a video starring people) can design the characters in a video without worrying about what actors are available and/or what CGI costs.